forc_util/

fs_locking.rs

use crate::{hash_path, user_forc_directory};
use std::{
    fs::{create_dir_all, read_dir, remove_file, File},
    io::{self, Read, Write},
    path::{Path, PathBuf},
};

/// Very simple AdvisoryPathMutex class
///
/// The goal of this struct is to signal other processes that a path is being used by another
/// process exclusively.
///
/// This struct will self-heal if the process that locked the file is no longer running.
pub struct PidFileLocking(PathBuf);

impl PidFileLocking {
    pub fn new<X: AsRef<Path>, Y: AsRef<Path>>(
        filename: X,
        dir: Y,
        extension: &str,
    ) -> PidFileLocking {
        // Try to cleanup stale files, ignore any errors as this is best-effort
        let _ = Self::cleanup_stale_files();

        let file_name = hash_path(filename);
        Self(
            user_forc_directory()
                .join(dir)
                .join(file_name)
                .with_extension(extension),
        )
    }

    /// Create a new PidFileLocking instance that is shared between the LSP and any other process
    /// that may want to update the file and needs to wait for the LSP to finish (like forc-fmt)
    pub fn lsp<X: AsRef<Path>>(filename: X) -> PidFileLocking {
        Self::new(filename, ".lsp-locks", "lock")
    }

    /// Checks if the given pid is active
    #[cfg(not(target_os = "windows"))]
    fn is_pid_active(pid: usize) -> bool {
        // Not using sysinfo here because it has compatibility issues with fuel.nix
        // https://github.com/FuelLabs/fuel.nix/issues/64
        use std::process::Command;
        let output = Command::new("ps")
            .arg("-p")
            .arg(pid.to_string())
            .output()
            .expect("Failed to execute ps command");

        let output_str = String::from_utf8_lossy(&output.stdout);
        output_str.contains(&format!("{pid} "))
    }

    #[cfg(target_os = "windows")]
    fn is_pid_active(pid: usize) -> bool {
        // Not using sysinfo here because it has compatibility issues with fuel.nix
        // https://github.com/FuelLabs/fuel.nix/issues/64
        use std::process::Command;
        let output = Command::new("tasklist")
            .arg("/FI")
            .arg(format!("PID eq {}", pid))
            .output()
            .expect("Failed to execute tasklist command");

        let output_str = String::from_utf8_lossy(&output.stdout);
        // Check if the output contains the PID, indicating the process is active
        output_str.contains(&format!("{}", pid))
    }

    /// Removes the lock file if it is not locked or the process that locked it is no longer active
    pub fn release(&self) -> io::Result<()> {
        if self.is_locked() {
            Err(io::Error::other(format!(
                "Cannot remove a dirty lock file, it is locked by another process (PID: {:#?})",
                self.get_locker_pid()
            )))
        } else {
            self.remove_file()?;
            Ok(())
        }
    }

    fn remove_file(&self) -> io::Result<()> {
        match remove_file(&self.0) {
            Err(e) => {
                if e.kind() != std::io::ErrorKind::NotFound {
                    return Err(e);
                }
                Ok(())
            }
            _ => Ok(()),
        }
    }

    /// Returns the PID of the owner of the current lock. If the PID is not longer active the lock
    /// file will be removed
    pub fn get_locker_pid(&self) -> Option<usize> {
        let fs = File::open(&self.0);
        if let Ok(mut file) = fs {
            let mut contents = String::new();
            file.read_to_string(&mut contents).ok();
            drop(file);
            if let Ok(pid) = contents.trim().parse::<usize>() {
                return if Self::is_pid_active(pid) {
                    Some(pid)
                } else {
                    let _ = self.remove_file();
                    None
                };
            }
        }
        None
    }

    /// Checks if the current path is owned by any other process. This will return false if there is
    /// no lock file or the current process is the owner of the lock file
    pub fn is_locked(&self) -> bool {
        self.get_locker_pid()
            .map(|pid| pid != (std::process::id() as usize))
            .unwrap_or_default()
    }

    /// Locks the given filepath if it is not already locked
    pub fn lock(&self) -> io::Result<()> {
        self.release()?;
        if let Some(dir) = self.0.parent() {
            // Ensure the directory exists
            create_dir_all(dir)?;
        }

        let mut fs = File::create(&self.0)?;
        fs.write_all(std::process::id().to_string().as_bytes())?;
        fs.sync_all()?;
        fs.flush()?;
        Ok(())
    }

    /// Cleans up all stale lock files in the .lsp-locks directory
    /// Returns a vector of paths that were cleaned up
    pub fn cleanup_stale_files() -> io::Result<Vec<PathBuf>> {
        let lock_dir = user_forc_directory().join(".lsp-locks");
        let entries = read_dir(&lock_dir)?;
        let mut cleaned_paths = Vec::new();

        for entry in entries {
            let entry = entry?;
            let path = entry.path();
            if let Some(ext) = path.extension().and_then(|ext| ext.to_str()) {
                if ext == "lock" {
                    if let Ok(mut file) = File::open(&path) {
                        let mut contents = String::new();
                        if file.read_to_string(&mut contents).is_ok() {
                            if let Ok(pid) = contents.trim().parse::<usize>() {
                                if !Self::is_pid_active(pid) {
                                    remove_file(&path)?;
                                    cleaned_paths.push(path);
                                }
                            } else {
                                remove_file(&path)?;
                                cleaned_paths.push(path);
                            }
                        }
                    }
                }
            }
        }
        Ok(cleaned_paths)
    }
}

/// Checks if the specified file is marked as "dirty".
/// This is used to prevent changing files that are currently open in an editor
/// with unsaved changes.
///
/// Returns `true` if a corresponding "dirty" flag file exists, `false` otherwise.
pub fn is_file_dirty<X: AsRef<Path>>(path: X) -> bool {
    PidFileLocking::lsp(path.as_ref()).is_locked()
}

#[cfg(test)]
mod test {
    use super::{user_forc_directory, PidFileLocking};
    use mark_flaky_tests::flaky;
    use std::{
        fs::{metadata, File},
        io::{ErrorKind, Write},
        os::unix::fs::MetadataExt,
    };

    #[test]
    fn test_fs_locking_same_process() {
        let x = PidFileLocking::lsp("test");
        assert!(!x.is_locked()); // checks the non-existence of the lock (therefore it is not locked)
        assert!(x.lock().is_ok());
        // The current process is locking "test"
        let x = PidFileLocking::lsp("test");
        assert!(!x.is_locked());
    }

    #[test]
    fn test_legacy() {
        // tests against an empty file (as legacy were creating this files)
        let x = PidFileLocking::lsp("legacy");
        assert!(x.lock().is_ok());
        // lock file exists,
        assert!(metadata(&x.0).is_ok());

        // simulate a stale lock file from legacy (which should be empty)
        let _ = File::create(&x.0).unwrap();
        assert_eq!(metadata(&x.0).unwrap().size(), 0);

        let x = PidFileLocking::lsp("legacy");
        assert!(!x.is_locked());
    }

    #[test]
    fn test_remove() {
        let x = PidFileLocking::lsp("lock");
        assert!(x.lock().is_ok());
        assert!(x.release().is_ok());
        assert!(x.release().is_ok());
    }

    #[test]
    fn test_fs_locking_stale() {
        let x = PidFileLocking::lsp("stale");
        assert!(x.lock().is_ok());

        // lock file exists,
        assert!(metadata(&x.0).is_ok());

        // simulate a stale lock file
        let mut x = File::create(&x.0).unwrap();
        x.write_all(b"191919191919").unwrap();
        x.flush().unwrap();
        drop(x);

        // PID=191919191919 does not exists, hopefully, and this should remove the lock file
        let x = PidFileLocking::lsp("stale");
        assert!(!x.is_locked());
        let e = metadata(&x.0).unwrap_err().kind();
        assert_eq!(e, ErrorKind::NotFound);
    }

    #[flaky]
    #[test]
    fn test_cleanup_stale_files() {
        // First create some test files
        let test_lock = PidFileLocking::lsp("test_cleanup");
        test_lock.lock().expect("Failed to create test lock file");

        // Create a test lock file with invalid PID
        let lock_path = user_forc_directory()
            .join(".lsp-locks")
            .join("test_cleanup_invalid.lock");

        // Write invalid content to ensure parsing fails
        {
            let mut file = File::create(&lock_path).expect("Failed to create test lock file");
            file.write_all(b"not-a-pid")
                .expect("Failed to write invalid content");
            file.flush().expect("Failed to flush file");
        }

        // Verify both files exist before cleanup
        assert!(
            test_lock.0.exists(),
            "Valid lock file should exist before cleanup"
        );
        assert!(
            lock_path.exists(),
            "Invalid lock file should exist before cleanup"
        );

        // Run cleanup and check returned paths
        let cleaned_paths =
            PidFileLocking::cleanup_stale_files().expect("Failed to cleanup stale files");

        // Verify that only the invalid lock file was cleaned up
        assert_eq!(cleaned_paths.len(), 1, "Expected one file to be cleaned up");
        assert_eq!(
            cleaned_paths[0], lock_path,
            "Expected invalid file to be cleaned up"
        );

        // Verify file system state
        assert!(test_lock.0.exists(), "Active lock file should still exist");
        assert!(!lock_path.exists(), "Lock file should be removed");

        // Cleanup after test
        test_lock.release().expect("Failed to release test lock");
    }
}